const Koa = require('koa')
const app = new Koa()
const views = require('koa-views')
const json = require('koa-json')
const onerror = require('koa-onerror')
const bodyparser = require('koa-bodyparser')
const logger = require('koa-logger')
const cors = require('koa2-cors');
const compress = require('koa-compress')
const conditional = require('koa-conditional-get')
const etag = require('koa-etag')


const index = require('./routes/index')
const users = require('./routes/users')

// error handler
onerror(app)

// middlewares
app.use(conditional())
app.use(etag())
// app.use((ctx) => {
//   let timer = new Date(Date.now() + 30000)
//   timer = timer.toGMTString()

//   ctx.set('Expires',timer)
//   ctx.body = 'HTTP强缓存之Expires'
// })

app.use(bodyparser({
  enableTypes:['json', 'form', 'text']
}))
app.use(cors())

app.use(compress({
  filter (content_type) {
  	return /text/i.test(content_type)
  },
  threshold: 2048,
  gzip: {
    flush: require('zlib').constants.Z_SYNC_FLUSH
  },
  deflate: {
    flush: require('zlib').constants.Z_SYNC_FLUSH,
  },
  br: false // disable brotli
}))

app.use(json())
app.use(logger())
app.use(require('koa-static')(__dirname + '/public'))

app.use(views(__dirname + '/views', {
  extension: 'pug'
}))

// logger
app.use(async (ctx, next) => {
  const start = new Date()
  await next()
  const ms = new Date() - start
  console.log(`${ctx.method} ${ctx.url} - ${ms}ms`)
})

// routes
app.use(index.routes(), index.allowedMethods())
app.use(users.routes(), users.allowedMethods())

// error-handling
app.on('error', (err, ctx) => {
  console.error('server error', err, ctx)
});

module.exports = app
